U.S. Pat. No. 3,131,036 to Hirschberg discloses a shoe drying device having a porous semi-rigid plastic foam wherein the foam defines a cavity which is filled with a powdered dessicant material.
U.S. Pat. No. 896,536 to Hayden discloses a shoe tree having an absorbent sponge material surrounded by a porous fabric, wherein a wooden block or piece is disposed within the sponge material to provide for insertion and removal of the shoe tree.
U.S. Pat. No. 2,173,528 to Beale discloses a disinfectant pad including an absorbent material enclosed by a porous covering.